When the world dies???What arrogence!!
The human race will not destroy the world... we will pollute the eco-sphere to the point where we can no longer survive in it and we'll die out.. in the procress we'll take a huge number of species with us... but in about 1000 years or so the planet will have completly healed itself and all that will be left of the great legacy of the human race will be a few left over plastic bags...
And hopefully, for the sake of the planet, that'll be the last time that evolution ever decides to deal the consiousness card...